Effect of routine zinc supplementation on pneumonia in children aged 6 months to 3 years: randomised controlled trial in an urban slum

Objectives To evaluate the effect of daily zinc supplementation in children on the incidence of acute lower respiratory tract infections and pneumonia. Design Double masked, randomised placebo controlled trial. Setting A slum community in New Delhi, India. Participants 2482 children aged 6 to 30 months. Interventions Daily elemental zinc, 10 mg to infants and 20 mg to older children or placebo for four months. Both groups received single massive dose of vitamin A (100 000 IU for infants and 200 000 IU for older children) at enrolment. Main outcome measures All households were visited weekly. Any children with cough and lower chest indrawing or respiratory rate 5 breaths per minute less than the World Health Organization criteria for fast breathing were brought to study physicians. Results At four months the mean plasma zinc concentration was higher in the zinc group (19.8 (SD 10.1) v 9.3 (2.1) mumol/l, P <0.001). The proportion of children who had acute lower respiratory, tract infection during follow up was no different in the two groups (absolute risk reduction - 0.2% 95% confidence interval - 3.9% to 3.6%). Zinc supplementation resulted in a lower incidence of pneumonia than placebo (absolute risk reduction 2.5%,, 95% confidence interval 0.4% to 4.6%). After correction for multiple episodes in the same child by generalised estimating equations analysis the odds ratio was 0.74, 95% confidence interval 0.56 to 0.99. Conclusions Zinc supplementation substantially reduced the incidence of pneumonia in children who had received vitamin A.